| Message ID | 20150304215551.7E6E22C3B7B@topped-with-meat.com |
|---|---|
| State | New |
| Headers | show |
On 03/04/2015 04:55 PM, Roland McGrath wrote: > In a bootstrapping environment, libstdc++ is likely not to be available > when building libc. This changes configure to check whether linking an > empty C++ program with ${CXX} works (it won't when libstdc++ is missing), > and elides all the C++ tests when that check fails. > > I've verified the check passes on a normal installation and fails in a > partially-installed cross-compilation environment lacking libstdc++. > > > Thanks, > Roland > > > 2015-03-04 Roland McGrath <roland@hack.frob.com> > > * configure.ac (libc_cv_cxx_link_ok): New check. > Reset CXX to empty if it fails to link. > * configure: Regenerated. > * dlfcn/Makefile (tests, modules-names): Add bug-atexit3 and > bug-atexit3-lib only if $(CXX) is nonempty. > * nptl/Makefile (tests): Likewise for tst-cancel24. > (tests, tests-static): Likewise for tst-cancel24-static. > * debug/Makefile (tests): Likewise for tst-chk4, tst-chk5, tst-chk6, > tst-lfschk4, tst-lfschk5, and tst-lfschk6. > I don't like this. The semantics I would rather have are that all such tests fail, not fail to build, but fail. Then the results of `make check` represent reality with all the C++ tests failing because you don't have a libstdc++. This way it's clear that you haven't passed all of the testing for glibc. Cheers, Carlos.
On 03/04/2015 10:55 PM, Roland McGrath wrote: > +# It's useless to us if it can't link programs (e.g. missing -lstdc++). > +AC_CACHE_CHECK([whether $CXX can link programs], libc_cv_cxx_link_ok, [dnl > +AC_LANG_PUSH([C++]) > +AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], > + [libc_cv_cxx_link_ok=yes], > + [libc_cv_cxx_link_ok=no]) > +AC_LANG_POP([C++])]) > +AS_IF([test $libc_cv_cxx_link_ok != yes], [CXX=]) The most common test failure is likely a working C++ compiler which cannot link libstdc++ statically. This causes a “make check” abort, without an error summary report. Your configure change does not address that at all.
> The most common test failure is likely a working C++ compiler which > cannot link libstdc++ statically. That's not something I've seen. > This causes a make check abort, without an error summary report. Your > configure change does not address that at all. Feel free to send a change to make the configure check more demanding. Thanks, Roland
> I don't like this. The semantics I would rather have are that all such > tests fail, not fail to build, but fail. Then the results of `make check` > represent reality with all the C++ tests failing because you don't have > a libstdc++. This way it's clear that you haven't passed all of the testing > for glibc. I don't like the conflation of unbuildable with failed. What we need is the possibility of UNSUPPORTED as an outcome for our tests. I'll send a change in that direction.
On 03/06/2015 07:37 PM, Roland McGrath wrote: >> I don't like this. The semantics I would rather have are that all such >> tests fail, not fail to build, but fail. Then the results of `make check` >> represent reality with all the C++ tests failing because you don't have >> a libstdc++. This way it's clear that you haven't passed all of the testing >> for glibc. > > I don't like the conflation of unbuildable with failed. What we need is > the possibility of UNSUPPORTED as an outcome for our tests. I'll send a > change in that direction. Good point. I like UNSUPPORTED better. My worry is that these tests simply go missing and we don't notice. Fail safe is better. Cheers, Carlos.
--- a/configure.ac +++ b/configure.ac @@ -50,9 +50,18 @@ if test $host != $build; then fi AC_SUBST(cross_compiling) AC_PROG_CPP +AC_CHECK_TOOL(READELF, readelf, false) + # We need the C++ compiler only for testing. AC_PROG_CXX -AC_CHECK_TOOL(READELF, readelf, false) +# It's useless to us if it can't link programs (e.g. missing -lstdc++). +AC_CACHE_CHECK([whether $CXX can link programs], libc_cv_cxx_link_ok, [dnl +AC_LANG_PUSH([C++]) +AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], + [libc_cv_cxx_link_ok=yes], + [libc_cv_cxx_link_ok=no]) +AC_LANG_POP([C++])]) +AS_IF([test $libc_cv_cxx_link_ok != yes], [CXX=]) if test "`cd $srcdir; /bin/pwd`" = "`/bin/pwd`"; then AC_MSG_ERROR([you must configure in a separate build directory]) --- a/debug/Makefile +++ b/debug/Makefile @@ -133,10 +133,13 @@ LDFLAGS-tst-backtrace6 = -rdynamic tests = backtrace-tst tst-longjmp_chk tst-chk1 tst-chk2 tst-chk3 \ tst-lfschk1 tst-lfschk2 tst-lfschk3 test-strcpy_chk test-stpcpy_chk \ - tst-chk4 tst-chk5 tst-chk6 tst-lfschk4 tst-lfschk5 tst-lfschk6 \ tst-longjmp_chk2 tst-backtrace2 tst-backtrace3 tst-backtrace4 \ tst-backtrace5 tst-backtrace6 +ifneq (,$(CXX)) +tests += tst-chk4 tst-chk5 tst-chk6 tst-lfschk4 tst-lfschk5 tst-lfschk6 +endif + extra-libs = libSegFault libpcprofile extra-libs-others = $(extra-libs) --- a/dlfcn/Makefile +++ b/dlfcn/Makefile @@ -36,12 +36,12 @@ endif ifeq (yes,$(build-shared)) tests = glrefmain failtest tst-dladdr default errmsg1 tstcxaatexit \ bug-dlopen1 bug-dlsym1 tst-dlinfo bug-atexit1 bug-atexit2 \ - bug-atexit3 tstatexit bug-dl-leaf tst-rec-dlopen + tstatexit bug-dl-leaf tst-rec-dlopen endif modules-names = glreflib1 glreflib2 glreflib3 failtestmod defaultmod1 \ defaultmod2 errmsg1mod modatexit modcxaatexit \ bug-dlsym1-lib1 bug-dlsym1-lib2 bug-atexit1-lib \ - bug-atexit2-lib bug-atexit3-lib bug-dl-leaf-lib \ + bug-atexit2-lib bug-dl-leaf-lib \ bug-dl-leaf-lib-cb moddummy1 moddummy2 failtestmod.so-no-z-defs = yes @@ -57,6 +57,11 @@ tststatic2-ENV = $(tststatic-ENV) tststatic3-ENV = $(tststatic-ENV) tststatic4-ENV = $(tststatic-ENV) tststatic5-ENV = $(tststatic-ENV) + +ifneq (,$(CXX)) +tests += bug-atexit3 +modules-names += bug-atexit3-lib +endif endif extra-test-objs += $(modules-names:=.os) --- a/nptl/Makefile +++ b/nptl/Makefile @@ -245,8 +245,8 @@ tests = tst-typesizes \ tst-cancel6 tst-cancel7 tst-cancel8 tst-cancel9 tst-cancel10 \ tst-cancel11 tst-cancel12 tst-cancel13 tst-cancel14 tst-cancel15 \ tst-cancel16 tst-cancel17 tst-cancel18 tst-cancel19 tst-cancel20 \ - tst-cancel21 tst-cancel22 tst-cancel23 tst-cancel24 tst-cancel25 \ - tst-cancel-self tst-cancel-self-cancelstate \ + tst-cancel21 tst-cancel22 tst-cancel23 $(if $(CXX),tst-cancel24) \ + tst-cancel25 tst-cancel-self tst-cancel-self-cancelstate \ tst-cancel-self-canceltype tst-cancel-self-testcancel \ tst-cleanup0 tst-cleanup1 tst-cleanup2 tst-cleanup3 tst-cleanup4 \ tst-flock1 tst-flock2 \ @@ -364,14 +364,19 @@ link-libc-static := $(common-objpfx)libc.a $(static-gnulib) \ $(common-objpfx)libc.a tests-static += tst-locale1 tst-locale2 tst-stackguard1-static \ - tst-cancel21-static tst-cancel24-static tst-cond8-static \ + tst-cancel21-static tst-cond8-static \ tst-mutex8-static tst-mutexpi8-static tst-sem11-static \ tst-sem12-static -tests += tst-stackguard1-static tst-cancel21-static tst-cancel24-static \ +tests += tst-stackguard1-static tst-cancel21-static \ tst-cond8-static tst-mutex8-static tst-mutexpi8-static \ tst-sem11-static tst-sem12-static xtests-static += tst-setuid1-static +ifneq (,$(CXX)) +tests += tst-cancel24-static +tests-static += tst-cancel24-static +endif + # These tests are linked with libc before libpthread tests-reverse += tst-cancel5 tst-cancel23 tst-vfork1x tst-vfork2x
In a bootstrapping environment, libstdc++ is likely not to be available when building libc. This changes configure to check whether linking an empty C++ program with ${CXX} works (it won't when libstdc++ is missing), and elides all the C++ tests when that check fails. I've verified the check passes on a normal installation and fails in a partially-installed cross-compilation environment lacking libstdc++. Thanks, Roland 2015-03-04 Roland McGrath <roland@hack.frob.com> * configure.ac (libc_cv_cxx_link_ok): New check. Reset CXX to empty if it fails to link. * configure: Regenerated. * dlfcn/Makefile (tests, modules-names): Add bug-atexit3 and bug-atexit3-lib only if $(CXX) is nonempty. * nptl/Makefile (tests): Likewise for tst-cancel24. (tests, tests-static): Likewise for tst-cancel24-static. * debug/Makefile (tests): Likewise for tst-chk4, tst-chk5, tst-chk6, tst-lfschk4, tst-lfschk5, and tst-lfschk6.